exe/

Location for files to be shared across model runs. Each file stored within exe/ is symbolically linked to each unique simulation directory in out/by-id/.

This is where you will find the compiled hymodelc executable as well as global model configuration files, including ASCDATA.CFG, CONC.CFG, LANDUSE.ASC, and ROUGLEN.ASC.

fortran/

Contains source code for the hymodelc executable and permute.f90 spatial permutation subroutine used for footprint kernel calculations. the included setup script (which runs as part of the standard uataq::stilt_init() installation) or manually with

Note that permute.f90 is compiled specially as an R-compatible dynamic link library, which allows its interactive use from within the R environment.

gfortran is used as the default compiler because it (1) is a universal free GNU fortran compiler and (2) has recently shown speed advantages over other popular paid compilers on test systems. To modify the compiler used for the fortran components of STILT, modify fortran/Makefile setting the compiler and relevant compilation flags and recompile.

out/

Initially empty, this folder propagates subdirectories containing simulation information and outputs. These are organized into the following three subdirectories for convenience.

footprints/

particles/

r/

Contains all R code that controls the model.

run_stilt.r is the primary script that users will interact with. It contains settings used to adjust model parameters, execute parallelized simulations, and calculate produce upstream influence footprints. These parameters are documented in Controls.

dependencies.r is used to load the necessary functions on each forked parallel process.

The src/ subdirectory contains the bulk of the R source code. Since the model is controlled by run_stilt.r, the source code found here will not be modified by the majority of users. Each file contains a single R function with metadata documenting function arguments and usage instructions for making programatic adjustments to STILT’s workflow.